When traveling abroad, the last thing we Americans want to do is offend the locals. Unfortunately, too many of us think that’s an easy trap to avoid: As long as you are polite, say “please” and “thank you,” don’t tell ethnic jokes about the local population, don’t act rude or all “ugly American”-like, and don’t walk around in an “FBI (Female Body Inspector)” T-shirt, you’ll be okay. Right?

Unfortunately, it’s not that simple. One downside of international travel is that it is shockingly easy for Americans to accidentally offend locals in a foreign country; some gestures or actions that mean absolutely nothing in the U.S. are considered extremely offensive abroad. If these unintentionally offensive American tourists are lucky, the locals will just seethe quietly or, even better, politely warn them of the offensiveness of their behavior. But at worst, it could lead to a nasty confrontation or, as has occurred in at least one case, a potential international incident.

Don’t let that happen to you. Here are 10 of the most accidentally offensive things Americans do overseas.

Using the left hand

ShutterstockIn certain countries (mostly in the Middle East, India, and parts of Africa), the left hand is considered very dirty because, historically, that was the hand used for certain sanitary activities.

So using it to initiate a handshake, touch food, touch someone else, or present a gift is considered pretty disgusting.

Sitting in the back seat of a taxi

Yahoo TravelWe all know the procedure: You hail a cab, wait until it stops, open the rear door, and climb into the back seat. Well, in Australia and New Zealand you’re doing OK — except for that last part. In those countries if you’re the sole passenger, some cabbies consider it extremely snobby for you to hop into the back seat as if they’re your chauffeur (which, if you think about it, they kind of are, at least for a while).

These cabbies prefer you to ride up front with them, as if you’re pals. Still, some travel guides suggest that female passengers nonetheless ride in the back seat for safety reasons.

Tipping

ShutterstockMany American travelers know that tipping isn’t expected in Europe. But not many know that in Japan, it could be taken as an insult. Before you go to any country, it’s a good practice to look up their tipping custom.

Putting your hand in your pocket

Giving a peace sign

ShutterstockIt doesn’t mean peace in the U.K., Ireland, Australia, or New Zealand. There, it’s an obscene gesture, the equivalent of what holding up half a peace sign (i.e., your middle finger) means here. Not exactly a gesture conducive to peace.

Showing the sole of your shoe

ShutterstockIt’s something that men in the U.S. often do without a second thought: sit down and then cross a foot over the opposite knee, exposing the sole of their shoe. But in much of the Middle East, this is extremely offensive: In Arab cultures, the soles of your shoes are considered dirty and shouldn’t be displayed to anyone.

Former U.S. Congressman Bill Richardson learned that lesson the hard way: On a delicate diplomatic mission to Iraq in 1995, Richardson crossed his leg in that fashion while talking to Saddam Hussein. The Iraqi leader was so offended, Richardson says, that he walked out of the room.

Crossing your fingers

ShutterstockSay you’re standing in a Vietnamese airport, and, hoping that you can get a seat on standby, you cross your fingers for good luck.

Don’t be surprised if people start staring at you. There, crossing the fingers is considered vulgar, as it’s said to resemble a certain female body part

Touching someone’s head

ShutterstockHere, it’s almost instinctive: You see a cute kid and pat him or her on the head.But that’s a big no-no in countries with high Buddhist populations, such as Sri Lanka, Thailand, and China.

Buddhists consider the head sacred; it’s where they believe the spirit lives. So hands off (and it’s probably not a good idea to walk around touching strangers, no matter where you are).

Giving the thumbs-up

ShutterstockHere’s a list of places where the thumbs-up is said to have various negative meanings: West Africa, South America, Iran, Sardinia, Israel, Thailand, Afghanistan, Italy, and Greece.

You can memorize the list, but it might be easier just to forget that you have thumbs while traveling overseas.

Giving the A-OK sign

ShutterstockIn the United States, this means A-OK. In Brazil and Germany, it means “a-hole.” It may also have unwanted connotations in France, Venezuela, and Turkey.